Sonoma County, CA Environmental Rules: Erosion Control (2026)
Key Facts
- Grading permit trigger
- Any cut, fill, or ground disturbance
- Regular grading cap
- 5,000 cu yd, 3-ft cut/fill, ≤15% slope
- Drainage permit trigger
- Facilities over 2 sq ft cross-section
- Permit term
- Expires 3 years from effective date
- Enforcement
- Stop-work order under Sec. 11.20.070
Summary
Unincorporated Sonoma County requires a construction grading permit before any cut, fill, or land-disturbing work over minor thresholds, plus a separate drainage permit for new or modified drainage facilities, under Chapter 11 of the county code.
A construction grading permit shall be required prior to commencing any construction grading or related work, including preparatory land clearing, vegetation removal, or other ground disturbance, except where exempted from permit requirements by Subsection C. A separate construction grading permit shall be required for each site.B.Designation and performance. Construction grading shall be designated "regular construction grading" or "engineered construction grading" in compliance with Table 11-1, and shall be performed as follows:1.Regular construction grading. Regular construction grading shall be performed in compliance with approved plans and specifications prepared by the property owner, an authorized agent of the property owner, or a licensed professional acting within the scope of their license.2.Engineered construction grading. Engineered construction grading shall be performed in compliance with approved plans and specifications prepared by a civil engineer. Table 11-1 Construction Grading Designation
Parameter Threshold Regular Construction Grading Engineered Construction Grading Volume (cut or fill) Does not exceed 5,000 cubic yards Exceeds 5,000 cubic yards Cut No greater than 3 feet in depth and does not create a cut slope greater than 5 feet in height 1 Greater than 3 feet in depth or creates a cut slope greater than 5 feet in height 1 Fill No greater than 3 feet in depth 1 Greater than 3 feet in depth 1
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 64 Update 2).
Full Breakdown
The county requires a construction grading permit before any cut, fill, land clearing, or ground disturbance not covered by an exemption in Sec. 11.04.010.C, such as minor cuts under 50 cubic yards or excavations tied to an existing building permit. Grading is designated 'regular' when volume stays under 5,000 cubic yards, cuts and fills stay under 3 feet, and existing slope is 15% or less; anything larger requires 'engineered' grading designed by a civil engineer. A separate construction drainage permit under Sec. 11.06.010 covers new or modified drainage facilities exceeding a 2-square-foot cross-section. Work done without a required permit, or in violation of a stop-work order, is a punishable violation under Sec. 11.20.070.
Violations & Fines
Working without a required permit, violating a stop-work order, or grading beyond approved plans is a code violation; the director may issue a stop-work order and pursue enforcement under Sec. 11.20.070.
Frequently Asked Questions
Does Sonoma County require a permit to grade my property?
What's the difference between regular and engineered grading?
Sources & Official References
Other rules in Sonoma County
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